The weak dielectric properties and the lack of magnetic loss of manganese-based absorbers are obstructed as the new generation of electromagnetic wave absorption(EMA)materials applying in microelectronic devices.Herei...The weak dielectric properties and the lack of magnetic loss of manganese-based absorbers are obstructed as the new generation of electromagnetic wave absorption(EMA)materials applying in microelectronic devices.Herein,the sulfuration and subsequent compounding strategies have been employed to enhance the EMA performance of multi-shell nanosphere-shaped Mn_(2)O_(3)materials.With the narrow bandgap,the as-obtained MnS possesses reinforced electrical conductivity,which is conducive to conductivity loss.More importantly,the presence of potential difference between different phases will form space charge region at the heterogeneous interface,thus favoring interfacial polarization.Additionally,the improvement of magnetic loss is attributed to the presence of Co_(3)O_(4)nanoparticles.Consequently,the composites present enhanced EMA performance than original Mn_(2)O_(3).Specifically,the minimum reflection loss of as-prepared composites is−51.4 dB at the thickness of 1.8 mm and the broad effective absorption bandwidth reaches 6.2 GHz at 1.9 mm.The low matching thickness and high absorption efficiency in this work can provide a convincing reference when designing distinguished manganese-based absorbers.展开更多
Optical bound states in the continuum(BICs)have recently stimulated a research boom,accompanied by demonstrations of abundant exotic phenomena and applications.With ultrahigh quality(Q)factors,optical BICs have powerf...Optical bound states in the continuum(BICs)have recently stimulated a research boom,accompanied by demonstrations of abundant exotic phenomena and applications.With ultrahigh quality(Q)factors,optical BICs have powerful abilities to trap light in optical structures from the continuum of propagation waves in free space.Besides the high Q factors enabled by the confined properties,many hidden topological characteristics were discovered in optical BICs.Especially in periodic structures with well-defined wave vectors,optical BICs were discovered to carry topological charges in momentum space,underlying many unique physical properties.Both high Q factors and topological vortex configurations in momentum space enabled by BICs bring new degrees of freedom to modulate light.BICs have enabled many novel discoveries in light-matter interactions and spin-orbit interactions of light,and BIC applications in lasing and sensing have also been well explored with many advantages.In this paper,we review recent developments of optical BICs in periodic structures,including the physical mechanisms of BICs,explored effects enabled by BICs,and applications of BICs.In the outlook part,we provide a perspective on future developments for BICs.展开更多
Fast-charging is highly demanded for applications requiring short charging time.However,fast-charging triggers serious problems,leading to decline in charge acceptance and energy efficiency,accelerated capacity degrad...Fast-charging is highly demanded for applications requiring short charging time.However,fast-charging triggers serious problems,leading to decline in charge acceptance and energy efficiency,accelerated capacity degradation,and safety risk.In this work,a three-electrode coin cell with a Li metal reference electrode is designed to individually record the potential of two electrodes,and measure the impedance of each electrode by using a power-optimized graphite-LiNi0.80Co0.15Al0.05O2 electrode couple.It is shown that regardless of the state-of-charge the Li-ion cell's impedance is contributed predominantly by the cathode,and that the cathode's impedance is dominated by the charge-transfer resistance.In consistence with the impedance results,polarization of the Li-ion cell is dominated by the cathode.It is surprised to find that no Li plating occurs on the graphite anode even if the charging rate is increased to 10 C(1 C=1.30 mA cm^−2).The results of this work indicate that low overall impedance with a high cathode-to-anode impedance ratio is the key to enabling safe fast-charging,and that fast-charging Li-ion batteries without Li plating on the graphite anode is possible if the cathode and graphite anode are optimistically engineered.展开更多
The interfacial characteristics of the Li metal anode(LMA)play a crucial role in its overall performance.Despite various materials being applied to modify the interface,a comprehensive understanding of their specific ...The interfacial characteristics of the Li metal anode(LMA)play a crucial role in its overall performance.Despite various materials being applied to modify the interface,a comprehensive understanding of their specific mechanisms remains to be investigated.Herein,we have prepared carbon cloth(CC)frameworks with their surfaces modified using ferromagnetic metal/LiF heterogeneous films(T^(M)-LiF-CC)as the substrate for LMA,which exhibit superior electrochemical performance.Utilizing ferromagnetic Co as a representative example,our study demonstrates that the enhanced performance of Co-LiF-CC,compared to bare CC,is attributed to the spinpolarized interface contributed by the Co/LiF heterostructure.Co and LiF play individual roles in redistributing electrons and Li^(+)to promote homogeneous Li deposition.Co nanoparticles play a crucial role in generating strong surface capacitance by storing electrons in spin-split bands,while LiF,with low surface diffusion barriers,ensures fast transportation of Li^(+).The Co-LiF-CC@Li electrodes deliver long lives of 7400 and 3600 h at 1 and 2 mA·cm^(-2)in symmetric cells,respectively;moreover,they enable full batteries with high and durable capacities,particularly when the N/P ratios are low(3.3 or even 1.7).展开更多
In April 2015,the Political Bureau of the CPC Central Committee adopted the“Outline of the Plan for the Coordinated Development of Beijing,Tianjin,and Hebei.”In July 2017,the“Plan for the Integrated Development of ...In April 2015,the Political Bureau of the CPC Central Committee adopted the“Outline of the Plan for the Coordinated Development of Beijing,Tianjin,and Hebei.”In July 2017,the“Plan for the Integrated Development of Beijing,Tianjin,and Hebei Talents(2017–2030),”jointly prepared by the leading groups of the three regions,was officially released.The core of the coordinated development of these three regions is the orderly removal of non-capital functions from Beijing.Talents,especially medical talents,are integral to this transition.The construction of a medical talent community across these three regions promotes the further development of a healthier China,meets the growing needs of the people for a better life,and embodies the concept of putting people first.This paper begins by examining the current situation of the construction of the Beijing-Tianjin-Hebei medical talent community,reviewing the progress made,analyzing existing problems,and proposing targeted countermeasures and suggestions.展开更多
Osmotic power generation in biomimetic nanofluidic systems has attracted considerable research interest owing to the enhanced performance and long-term stability. Towards practical applications, when extrapolating the...Osmotic power generation in biomimetic nanofluidic systems has attracted considerable research interest owing to the enhanced performance and long-term stability. Towards practical applications, when extrapolating the materials from single-nanopore to multi-pore membranes, conventional viewpoint suggests that, to gain high electric power density, the porosity should be as high as possible. However, recent experimental observations show that the commonly-used linear amplification method largely overestimates the actual performance, particularly at high pore density. Herein, we provide a theoretical investigation to understand the reason. We find a counterintuitive pore-density dependence in high porosity nanofluidic systems that, once the pore density approaches more than lx109 pores/cm2, the overall output electric power goes down with the increasing pore density. The excessively high pore density impairs the charge selectivity and induces strong ion concentration polarization, which undermines the osmotic power generation process. By optimizing the geometric size of the nanopores, the performance degradation can be effectively relieved. These findings clarify the origin of the unsatisfactory performance of the current osmotic nanofluidic power sources, and provide insights to further optimize the device.展开更多
It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) wi...It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) with layered structure was explored as the 2e^(-) ORR electrocatalyst,which not only showed the highest 2e^(-) selectivity more than 97%,but also delivered a slight activity decay after 5000 cycles in alkaline media.Moreover,when NiTe_(2) was assembled as the electrocatalyst in H-type electrolyzer,the on-site yield of H_(2)O_(2) could reach up to 672 mmol h^(-1)g^(-1) under 0.45 V vs.RHE.Further in situ Raman spectra,theoretical calculation and post microstructural analysis synergistically unveiled that such a good 2e^(-) ORR performance could be credited to the intrinsic layered crystal structure,the high compositional stability,as well as the electron modulation on the active site Ni atoms by neighboring Te atoms,leading to the exposure of active sites as well as the optimized adsorption free energy of Ni to –OOH.More inspiringly,such telluride electrocatalyst has also been demonstrated to exhibit high activity and selectivity towards 2e^(-) ORR in neutral media.展开更多
Stem cells from human exfoliated deciduous teeth(SHED)uniquely exhibit high proliferative and neurogenic potential.Charged biomaterials have been demonstrated to promote neural differentiation of stem cells,but the do...Stem cells from human exfoliated deciduous teeth(SHED)uniquely exhibit high proliferative and neurogenic potential.Charged biomaterials have been demonstrated to promote neural differentiation of stem cells,but the dose-response effect of electrical stimuli from these materials on neural differentiation of SHED remains to be elucidated.Here,by utilizing different annealing temperatures prior to corona poling treatment,BaTiO_(3)/P(VDF-TrFE)ferroelectric nanocomposite membranes with varying charge polarization intensity(d_(33)≈0,4,12 and 19 pC N^(-1))were fabricated.Enhanced expression of neural markers,increased cell elongation and more prominent neurite outgrowths were observed with increasing surface charge of the nanocomposite membrane indicating a dose-response effect of surface electrical charge on SHED neural differentiation.Further investigations of the underlying molecular mechanisms revealed that intracellular calcium influx,focal adhesion formation,FAK-ERK mechanosensing pathway and neurogenic-related ErbB signaling pathway were implicated in the enhancement of SHED neural differentiation by surface electrical charge.Hence,this study confirms the dose-response effect of biomaterial surface charge on SHED neural differentiation and provides preliminary insights into the molecular mechanisms and signaling pathways involved.展开更多
We present a study of electronic properties of zigzag graphene nanoribbons （ZGNRs） substitutionally doped with nitrogen atoms at a single edge by first principle calculations. We find that the two edge states near t...We present a study of electronic properties of zigzag graphene nanoribbons （ZGNRs） substitutionally doped with nitrogen atoms at a single edge by first principle calculations. We find that the two edge states near the Fermi level sepa- rate due to the asymmetric nitrogen-doping. The ground states of these systems become ferromagnetic because the local magnetic moments along the undoped edges remain and those along the doped edges are suppressed. By controlling the charge-doping level, the magnetic moments of the whole ribbons are modulated. Proper charge doping leads to interest- ing half-metallic and single-edge conducting ribbons which would be helpful for designing graphene-nanoribbon-based spintronic devices in the future.展开更多
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2019YQ24)Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites).
文摘The weak dielectric properties and the lack of magnetic loss of manganese-based absorbers are obstructed as the new generation of electromagnetic wave absorption(EMA)materials applying in microelectronic devices.Herein,the sulfuration and subsequent compounding strategies have been employed to enhance the EMA performance of multi-shell nanosphere-shaped Mn_(2)O_(3)materials.With the narrow bandgap,the as-obtained MnS possesses reinforced electrical conductivity,which is conducive to conductivity loss.More importantly,the presence of potential difference between different phases will form space charge region at the heterogeneous interface,thus favoring interfacial polarization.Additionally,the improvement of magnetic loss is attributed to the presence of Co_(3)O_(4)nanoparticles.Consequently,the composites present enhanced EMA performance than original Mn_(2)O_(3).Specifically,the minimum reflection loss of as-prepared composites is−51.4 dB at the thickness of 1.8 mm and the broad effective absorption bandwidth reaches 6.2 GHz at 1.9 mm.The low matching thickness and high absorption efficiency in this work can provide a convincing reference when designing distinguished manganese-based absorbers.
基金supported by the National Natural Science Foundation of China(Nos.12234007,12221004,12321161645,62325501,62135001,12074049,and 12147102)the National Key R and D Program of China(Nos.2022YFA1404804,2021YFA1400603,and 2023YFA1406900)+4 种基金the Major Program of National Natural Science Foundation of China(Nos.T2394480 and T2394481)the Science and Technology Commission of Shanghai Municipality(Nos.22142200400,21DZ1101500,2019SHZDZX01,and 23DZ2260100)the Fundamental Research Funds for the Central Universities(No.2022CDJQY-007)supported by the China National Postdoctoral Program for Innovative Talents(No.BX20230079)the China Postdoctoral Science Foundation(No.2023M740721).
文摘Optical bound states in the continuum(BICs)have recently stimulated a research boom,accompanied by demonstrations of abundant exotic phenomena and applications.With ultrahigh quality(Q)factors,optical BICs have powerful abilities to trap light in optical structures from the continuum of propagation waves in free space.Besides the high Q factors enabled by the confined properties,many hidden topological characteristics were discovered in optical BICs.Especially in periodic structures with well-defined wave vectors,optical BICs were discovered to carry topological charges in momentum space,underlying many unique physical properties.Both high Q factors and topological vortex configurations in momentum space enabled by BICs bring new degrees of freedom to modulate light.BICs have enabled many novel discoveries in light-matter interactions and spin-orbit interactions of light,and BIC applications in lasing and sensing have also been well explored with many advantages.In this paper,we review recent developments of optical BICs in periodic structures,including the physical mechanisms of BICs,explored effects enabled by BICs,and applications of BICs.In the outlook part,we provide a perspective on future developments for BICs.
基金This work was financially supported by the National Natural Science Foundation of China (Nos.21471141,U1532135,11375198,11574280,and U1532112),the Recruitment Program of Global Experts,the CAS Hundred Talent Program,the Hefei Science Center CAS(Nos.2015HSC-UP009 and 2015HSC-UP020),and the Fundamental Research Funds for the Central Universities (Nos.WK2060190025 and WK2310000035).
基金Funding information Army Research Laboratory,Grant/Award Number:N/A
文摘Fast-charging is highly demanded for applications requiring short charging time.However,fast-charging triggers serious problems,leading to decline in charge acceptance and energy efficiency,accelerated capacity degradation,and safety risk.In this work,a three-electrode coin cell with a Li metal reference electrode is designed to individually record the potential of two electrodes,and measure the impedance of each electrode by using a power-optimized graphite-LiNi0.80Co0.15Al0.05O2 electrode couple.It is shown that regardless of the state-of-charge the Li-ion cell's impedance is contributed predominantly by the cathode,and that the cathode's impedance is dominated by the charge-transfer resistance.In consistence with the impedance results,polarization of the Li-ion cell is dominated by the cathode.It is surprised to find that no Li plating occurs on the graphite anode even if the charging rate is increased to 10 C(1 C=1.30 mA cm^−2).The results of this work indicate that low overall impedance with a high cathode-to-anode impedance ratio is the key to enabling safe fast-charging,and that fast-charging Li-ion batteries without Li plating on the graphite anode is possible if the cathode and graphite anode are optimistically engineered.
基金financially supported by the National Natural Science Foundation of China(No.52002270)the China Postdoctoral Science Foundation(No.2020M670661)。
文摘The interfacial characteristics of the Li metal anode(LMA)play a crucial role in its overall performance.Despite various materials being applied to modify the interface,a comprehensive understanding of their specific mechanisms remains to be investigated.Herein,we have prepared carbon cloth(CC)frameworks with their surfaces modified using ferromagnetic metal/LiF heterogeneous films(T^(M)-LiF-CC)as the substrate for LMA,which exhibit superior electrochemical performance.Utilizing ferromagnetic Co as a representative example,our study demonstrates that the enhanced performance of Co-LiF-CC,compared to bare CC,is attributed to the spinpolarized interface contributed by the Co/LiF heterostructure.Co and LiF play individual roles in redistributing electrons and Li^(+)to promote homogeneous Li deposition.Co nanoparticles play a crucial role in generating strong surface capacitance by storing electrons in spin-split bands,while LiF,with low surface diffusion barriers,ensures fast transportation of Li^(+).The Co-LiF-CC@Li electrodes deliver long lives of 7400 and 3600 h at 1 and 2 mA·cm^(-2)in symmetric cells,respectively;moreover,they enable full batteries with high and durable capacities,particularly when the N/P ratios are low(3.3 or even 1.7).
文摘In April 2015,the Political Bureau of the CPC Central Committee adopted the“Outline of the Plan for the Coordinated Development of Beijing,Tianjin,and Hebei.”In July 2017,the“Plan for the Integrated Development of Beijing,Tianjin,and Hebei Talents(2017–2030),”jointly prepared by the leading groups of the three regions,was officially released.The core of the coordinated development of these three regions is the orderly removal of non-capital functions from Beijing.Talents,especially medical talents,are integral to this transition.The construction of a medical talent community across these three regions promotes the further development of a healthier China,meets the growing needs of the people for a better life,and embodies the concept of putting people first.This paper begins by examining the current situation of the construction of the Beijing-Tianjin-Hebei medical talent community,reviewing the progress made,analyzing existing problems,and proposing targeted countermeasures and suggestions.
文摘Osmotic power generation in biomimetic nanofluidic systems has attracted considerable research interest owing to the enhanced performance and long-term stability. Towards practical applications, when extrapolating the materials from single-nanopore to multi-pore membranes, conventional viewpoint suggests that, to gain high electric power density, the porosity should be as high as possible. However, recent experimental observations show that the commonly-used linear amplification method largely overestimates the actual performance, particularly at high pore density. Herein, we provide a theoretical investigation to understand the reason. We find a counterintuitive pore-density dependence in high porosity nanofluidic systems that, once the pore density approaches more than lx109 pores/cm2, the overall output electric power goes down with the increasing pore density. The excessively high pore density impairs the charge selectivity and induces strong ion concentration polarization, which undermines the osmotic power generation process. By optimizing the geometric size of the nanopores, the performance degradation can be effectively relieved. These findings clarify the origin of the unsatisfactory performance of the current osmotic nanofluidic power sources, and provide insights to further optimize the device.
基金supported by the National MCF Energy R&D Program of China (2018YFE0306105)the National Key R&D Program of China (2020YFA0406104, 2020YFA0406101)+8 种基金the Innovative Research Group Project of the National Natural Science Foundation of China (51821002)the National Natural Science Foundation of China (52201269, 52302296, 51972216)the Natural Science Foundation of Jiangsu Province (BK20220028, BK20210735)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province (21KJB430043)the Collaborative Innovation Center of Suzhou Nano Science & Technology, the 111 Projectthe Suzhou Key Laboratory of Functional Nano & Soft Materials, the Jiangsu Key Laboratory for Advanced Negative Carbon Technologiesthe Science and Technology Development Fund, Macao SAR (0009/2022/ITP)the funding from Gusu leading talent plan for scientific and technological innovation and entrepreneurship (ZXL2022487)China Scholarship Council (CSC) for the Ph.D. fellowship。
文摘It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) with layered structure was explored as the 2e^(-) ORR electrocatalyst,which not only showed the highest 2e^(-) selectivity more than 97%,but also delivered a slight activity decay after 5000 cycles in alkaline media.Moreover,when NiTe_(2) was assembled as the electrocatalyst in H-type electrolyzer,the on-site yield of H_(2)O_(2) could reach up to 672 mmol h^(-1)g^(-1) under 0.45 V vs.RHE.Further in situ Raman spectra,theoretical calculation and post microstructural analysis synergistically unveiled that such a good 2e^(-) ORR performance could be credited to the intrinsic layered crystal structure,the high compositional stability,as well as the electron modulation on the active site Ni atoms by neighboring Te atoms,leading to the exposure of active sites as well as the optimized adsorption free energy of Ni to –OOH.More inspiringly,such telluride electrocatalyst has also been demonstrated to exhibit high activity and selectivity towards 2e^(-) ORR in neutral media.
基金supported by the National Key Research and Development Program of China(2021YFB3800800,2021YFC2400400)the National Natural Science Foundation of China(Nos.82022016,81991505,51973004,52103312)+1 种基金the Beijing Municipal Natural Science Foundation(7222226)Peking University Medicine Fund(PKU2020LCXQ009).
文摘Stem cells from human exfoliated deciduous teeth(SHED)uniquely exhibit high proliferative and neurogenic potential.Charged biomaterials have been demonstrated to promote neural differentiation of stem cells,but the dose-response effect of electrical stimuli from these materials on neural differentiation of SHED remains to be elucidated.Here,by utilizing different annealing temperatures prior to corona poling treatment,BaTiO_(3)/P(VDF-TrFE)ferroelectric nanocomposite membranes with varying charge polarization intensity(d_(33)≈0,4,12 and 19 pC N^(-1))were fabricated.Enhanced expression of neural markers,increased cell elongation and more prominent neurite outgrowths were observed with increasing surface charge of the nanocomposite membrane indicating a dose-response effect of surface electrical charge on SHED neural differentiation.Further investigations of the underlying molecular mechanisms revealed that intracellular calcium influx,focal adhesion formation,FAK-ERK mechanosensing pathway and neurogenic-related ErbB signaling pathway were implicated in the enhancement of SHED neural differentiation by surface electrical charge.Hence,this study confirms the dose-response effect of biomaterial surface charge on SHED neural differentiation and provides preliminary insights into the molecular mechanisms and signaling pathways involved.
基金supported by the National Natural Science Foundation of China(Grant Nos.10834012 and 11374342)National Key Basic Research and Development Program of China(Grant No.2009CB930700)the Knowledge Innovation Foundation of the Chinese Academy of Sciences(Grant No.KJCX2-YW-W35)
文摘We present a study of electronic properties of zigzag graphene nanoribbons （ZGNRs） substitutionally doped with nitrogen atoms at a single edge by first principle calculations. We find that the two edge states near the Fermi level sepa- rate due to the asymmetric nitrogen-doping. The ground states of these systems become ferromagnetic because the local magnetic moments along the undoped edges remain and those along the doped edges are suppressed. By controlling the charge-doping level, the magnetic moments of the whole ribbons are modulated. Proper charge doping leads to interest- ing half-metallic and single-edge conducting ribbons which would be helpful for designing graphene-nanoribbon-based spintronic devices in the future.
